Re: [PATCH 1/3] arm64: ptrace: Add is_syscall_success to handle compat

The general version of is_syscall_success does not handle 32-bit compatible case, which would cause 32-bit negative return code to be recoganized as a positive number later and seen as a "success". Since is_compat_thread is defined in compat.h, implementing is_syscall_success in ptrace.h would introduce build failure due to recursive inclusion of some basic headers like mutex.h. We put the implementation to ptrace.c Signed-off-by: He Zhe <zhe.he(a)windriver.com&gt; --- arch/arm64/include/asm/ptrace.h | 3 +++ arch/arm64/kernel/ptrace.c | 10 ++++++++++ 2 files changed, 13 insertions(+) diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h index e58bca832dff..3c415e9e5d85 100644 --- a/arch/arm64/include/asm/ptrace.h +++ b/arch/arm64/include/asm/ptrace.h @@ -328,6 +328,9 @@ static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) regs->regs[0] = rc; } +extern inline int is_syscall_success(struct pt_regs *regs); +#define is_syscall_success(regs) is_syscall_success(regs) + /** * regs_get_kernel_argument() - get Nth function argument in kernel * @regs: pt_regs of that context diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 170f42fd6101..3266201f8c60 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1909,3 +1909,13 @@ int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task) else return valid_native_regs(regs); } + +inline int is_syscall_success(struct pt_regs *regs) +{ + unsigned long val = regs->regs[0]; + + if (is_compat_thread(task_thread_info(current))) + val = sign_extend64(val, 31); + + return !IS_ERR_VALUE(val); +}